The tire beads of a green tire, prior to vulcanization, formed by a tire molding step of a tire manufacturing process are liable to deform due to conditions of storage and temperature difference between the green tire and the ambient air. When a hanger-type carriage is used for storing and carrying green tires, the tire beads expected to be completely round are deformed in an elliptic shape by their own weight.
A vulcanized tire obtained by vulcanizing the deformed green tire is unsatisfactory in quality represented by uniformity and balance and a vulcanized tire of a satisfactory quality cannot be produced.
A tire shape correcting and holding device is proposed in Patent document 1 (JP 2002-79589 A). This tire shape correcting and holding device has a pair of upper and lower arcuate shaping plates divided into a plurality of segments. The pair of arcuate shaping plates are inserted in a green tire to be subjected to a vulcanizing process. The pair of shaping plates are pressed against the axially opposite upper and lower tire beads of a green tire and are expanded to correct the deformed tire beads and to shape the tire beads into a completely round shape.
The pair of shaping plates of the shape correcting and holding device proposed in Patent document 1 are expanded to press the upper and lower tire beads radially outward to shape the tire beads in a completely round shape. The corrected green tire held by the shape correcting and holding device is sent to a vulcanizer.